The present invention relates to the field of washing machines, comprising a wash tub that is filled with wash water and that has a drain opening, a drain pump, a drain line that connects the water in the wash tub to the drain pump and a valve part that is connected to the wash tub in a sealed fashion, and comprising a pipe part that is connected to the drain pump for water transfer, with the washing machine also having a drain valve that can float in the wash water, said valve being disposed moveably inside the valve part in order to seal the drain opening when wash water is located inside the wash tub and when the drain pump is idle, or in order to open the drain opening when no wash water is located inside the wash tub or when the drain pump is operating.